Our specific aims are to: (1) establish the number of sweat pores per unit area by counting pores on the surface of epidermal ridges in normal individuals, (2) to count the number of sweat pores per unit area on the surface of epidermal ridges in females who present with agenesis of permanent teeth excluding third molars, (3) to apply this technique to individuals known to have hypohidrotic ectodermal dysplasia and their families, (4) (a) to establish if there is a correlation between congenitally missing teeth (excluding third molars) and reduced sweat pore count and (b) to establish if there is a correlation between the number of missing teeth and reduced sweat pore counts. The future aim is to establish a diagnostic screening procedure to identify females who present with agenesis of teeth as potential carriers of hypohidrotic ectodermal dysplasia. In order to achieve these aims, hypothenar eminence impressions of both hands will be taken of 35 normal individuals and 35 females who present with agenesis of permanent teeth (excluding third molars). Impressions will be taken using a vinyl polysiloxanl impression material (Mirror-3TM, Sybron/Kerr), replicas produced and prepared for scanning electron microscope viewing. Pores will be counted along epidermal ridges encompassing an area of .5 sq. cm. Comparisons of results will be made between the normal population, the hypodontia population and the individuals known to have hypohidrotic ectodermal dysplasia and their families.